Hunting dark energy with gravity resonance spectroscopy

Dark Energy is widely believed by many to be the driving force behind the universe’s rapid expansion. There are several theories that attempt to explain this mysterious phenomenon. These theories suggest that Dark Energy's influence on quantum scales is vanishingly tiny, but experiments have not been able to verify or discredit these theories. Hartmut Abele, a researcher at TU Wien, Austria, has published new research in EPJ ST. This team shows how ultra-cold neutrons can be used to study one theory. Their approach, called "Gravity Resonance Spectrum" (GRS), could help researchers understand one of the most mysterious aspects of cosmology.As a candidate for Dark Energy, previously proposed phenomena called'scalar-symmetron field'. These fields, if they do exist, will be much weaker than gravity -- the weakest fundamental force in physics. Researchers could therefore prove their existence experimentally by looking for subtle anomalies in quantum particles trapped within gravitational fields. Ultra-cold neutrons in a gravitational field can take several distinct quantum states. These state changes depend on the strength of that field. These neutrons can be made to move to higher-energy states through GRS. This is possible thanks to the precise mechanical oscillations of a nearly perfect mirror. Any deviations from the expected energy differences between these states could indicate Dark Energy.Abele's group developed and demonstrated a GRS experiment called 'qBOUNCE'. It was based on a technique called Ramsey spectroscopy. The experiment involved creating neutrons that transition from low-energy to high-energy quantum states in an ultracold beam. After scattering away any undesirable states, the detector picked up the rest of the neutrons. Researchers were able to place much more precise limits on the parameters of the scalar-symmetron field parameters by precisely measuring the energy differences between different states. This technique opens the door to future research that will allow for more precise searches of Dark Energy.